Certain automotive vehicles are equipped with an automatic “Stop-Start System”, which automatically shuts down and restarts the engine of the vehicle to reduce fuel consumption of the vehicle under certain conditions, such as when the vehicle would otherwise idle. In operation, an automotive vehicle stop-start system detects when the vehicle has stopped (wherein the engine would otherwise be idling), at which time the system shuts the engine down. When power from the engine is required, e.g., the driver releases the brakes, the engine is automatically restarted. Other examples of when an automatic stop-start system may be employed are also possible. In any event, when a stop-start vehicle is in the auto-stop mode, i.e., the engine it shut down, the vehicle battery must supply power to electrical devices and components in the vehicle. In automotive vehicles with an electrically-actuated parking brake, the electrical power required to actuate the electric brake (i.e., apply the brake or release the brake) can be substantial, (on the order of about 45 amps), for a relatively short period of time (about 1 second). Under certain battery conditions, the battery may have insufficient power to power the electric brake actuator and the starter (to re-start the vehicle) at the same time.
In known automatic stop-start vehicles, the automatic stop-start system would be disabled when the level of the vehicle battery was below a certain threshold sufficient to enable the system to activate the electric parking brake and the vehicle starter both at the same time. The inventors hereof have developed a system and method of controlling an automotive vehicle stop-start system that permits the vehicle stop-start system to function at lower battery levels than previous known systems.